A natural way to quantify the negativity of the Wigner representation of a given state \(\rho \)  is to measure the total quasi-probability for which the function \(W_\rho (\beta )\)  takes negative values [1]}, i.e.
\(N_W(\rho )= \int \beta ^2\frac{|W_\rho (\beta )| -W_\rho (\beta )}{2},\) 
